It is already known that certain phenyl-substituted cyclic ketoenols are active as insecticides, acaricides and/or herbicides.
1H-arylpyrrolidine-dione derivatives (EP-A-456 063, EP-A-521 334, EP-A-596 298, EP-A-613 884, EP-A-613 885, DE 44 40 594, WO 94/01 997, WO 95/01 358, WO 95/20 572, EP-A-668 267, WO 95/26 954, WO 96/25395 and WO 96/35 664) having insecticidal, acaricidal and in some cases herbicidal activity are known.
It is known that certain substituted .DELTA..sup.3 -dihydrofuran-2-one-derivatives have herbicidal properties (cf. DE-A-4 014 420). The synthesis of the tetronic acid derivatives (such as, for example, 3-(2-methyl-phenyl)-4-hydroxy-5-(4-fluorophenyl)-.DELTA..sup.3 -dihydrofuran-(2)-one) used as starting materials is also described in DE-A-4 014 420. Compounds of a similar structure are known from the publication Campbell et al., J. Chem. Soc., Perkin Trans. 1, 1985, (8) 1567-76, without an insecticidal and/or acaricidal activity being mentioned. Furthermore, 3-aryl-.DELTA..sup.3 -dihydrofuranone derivatives having herbicidal, acaricidal and insecticidal properties are known from EP-A-528 156, EP-A-0 647 637, WO 96/25395, WO 96/20196 and the abovementioned hitherto undisclosed patent application. 3-aryl-.DELTA..sup.3 -dihydrothiophene-one derivatives are also known (WO 95/26 345, WO 96/25395 and WO 96/35664).
However, the acaricidal and insecticidal activity and/or spectrum of activity and/or plant tolerance of these compounds, in particular with respect to crop plants, is not always satisfactory.